Optical Microscopy of the Pediatric Vocal Fold

Abstract

Objectives: To compare and contrast 4 optical imaging techniques for evaluating the developing microstructure of the pediatric vocal fold and to identify the optimal strategy for in vivo imaging. Design: Prospective study. Setting: Academic medical center. Patients: A total of 6 laryngeal specimens: 5 pediatric (ages 10 months to 16 years) (4 from cadavers and 1 from a living patient immediately after laryngectomy) and 1 cadaveric young adult specimen (age, 23 years). Intervention: Sequential noninvasive optical imaging of pediatric vocal fold specimens using optical frequency domain imaging (OFDI), angle-resolved OFDI (AR-OFDI), spectrally encoded confocal microscopy (SECM), and full-field optical coherence microscopy (FF-OCM), followed by fixation, sectioning, and histologic analysis of the same specimen for comparison. Main Outcome Measure: Correlation between the microstructure observed using the 4 noninvasive optical imaging techniques and with the results of histopathologic analysis for the same specimen. Results: A successful in vivo imaging technique for developmental assessment of the pediatric vocal fold would include visualization of distinct layers (epithelium, lamina propria, and muscularis mucosa) and allow for identification of the individual cells composing the layers. The OFDI and AR-OFDI techniques provide a global assessment of the microstructure of the pediatric vocal fold to a depth of 1200 mu m but lack the ability to distinguish cellular and subcellular structures. The FF-OCM technique allows for visualization with improved cellular detail (1-mu m resolution), but the image acquisition speed is too slow for clinical use. The SECM technique has a faster acquisition rate and shows good cellular and subcellular detail to a depth of 250 mu m. Conclusions: The OFDI and SECM techniques were identified as promising and complementary candidates for in vivo cellular and subcellular imaging of the epithelium, basement membrane, and lamina propria of the pediatric vocal fold. To further validate the clinical potential of these techniques, a handheld SECM probe has been developed and demonstrated for in vivo evaluation of the pediatric vocal fold.